In reply to @SeTSeR:matrix.org
Hello, I'm trying to build NixOS image for Starfive VisionFive 2 using this repo:
https://github.com/NickCao/nixos-riscv
I was able to build vanilla image, but the problems arose when I tried to add `xrdp` to it. Compilation of xrdp began to fail with bizarre errors on `pkg-config` missing. I looked into derivation for xrdp and found out that for some reason that `xorgxrdp` has dependency on `pkg-config` from host, not from build. It's very strange, given that it is placed in `nativeBuildInputs`, just like `autoconf` and `automake`, which behave correctly:
https://github.com/NixOS/nixpkgs/blob/d934204a0f8d9198e1e4515dd6fec76a139c87f0/pkgs/applications/networking/remote/xrdp/default.nix#L49
How can this be? How can I fix this?

Unfortunately, such errors seem to be fairly common in wrapped packages (which is the case with pkg-config).

I couldn't tell you why the splicing is going wrong, but perhaps overriding xrdp to use pkg-config-unwrapped will work?
If it does, something in the wrapper is causing splicing to break.

diff --git a/pkgs/applications/networking/remote/xrdp/default.nix b/pkgs/applications/networking/remote/xrdp/default.nix
index c9f679d9e124..700a040e9f14 100644
--- a/pkgs/applications/networking/remote/xrdp/default.nix
+++ b/pkgs/applications/networking/remote/xrdp/default.nix
@@ -58,6 +58,9 @@ let
       substituteInPlace configure.ac \
         --replace 'moduledir=`pkg-config xorg-server --variable=moduledir`' "moduledir=$out/lib/xorg/modules" \
         --replace 'sysconfdir="/etc"' "sysconfdir=$out/etc"
+
+      substituteInPlace bootstrap \
+        --replace-fail "command -v pkg-config" "command -v $PKG_CONFIG"
     '';

     preConfigure = "./bootstrap";
@@ -94,10 +97,13 @@ let
       substituteInPlace sesman/xauth.c --replace "xauth -q" "${xorg.xauth}/bin/xauth -q"

       substituteInPlace configure.ac --replace /usr/include/ ""
+
+      substituteInPlace bootstrap librfxcodec/bootstrap \
+        --replace-fail "command -v pkg-config" "command -v $PKG_CONFIG"
     '';

     preConfigure = ''
-      (cd librfxcodec && ./bootstrap && ./configure --prefix=$out --enable-static --disable-shared)
+      (cd librfxcodec && ./bootstrap && ./configure --prefix=$out --enable-static --disable-shared --host=${stdenv.hostPlatform.config})
       ./bootstrap
     '';
     dontDisableStatic = true;